Plotting all 7948 full-circle rings. Towers are coloured by tenor weight: see map key for details.

Key

	up to 2.5 cwt
	2.5 to 5 cwt
	5 to 8 cwt
	8 to 12 cwt
	12 to 16 cwt
	16 to 20 cwt
	20 to 25 cwt
	25 to 30 cwt
	30 to 40 cwt
	40 cwt or more